Modern railroad tracks are constructed using long sections of ribbon rail. The sections are often found in lengths up to about 1600 feet but can range up to 2000 feet or longer. Shorter sections of lengths as little as 300-320 feet are also available. These sections of ribbon rail are formed by butt-welding multiple sticks of rail, which traditionally come from a steel mill in thirty-nine foot or seventy-eight foot lengths. The welding of the ribbon rails is done at a welding plant and the welded ribbon rails are transported to their installation site on a specially constructed rail train. When existing track is being replaced, ribbon rails may be unloaded from the rail train using a rail unloading machine, such as the Rail unloading machines disclosed in U.S. Pat. Nos. 6,981,452 and 7,707,943, both to Herzog et al. The rail-unloading machine pulls one or two rails off of the rail train as the rail train moves down the existing track and lays it alongside the existing rails.
Prior art rail trains traditionally comprise of a plurality of sixty-foot-long flatcars connected together by standard railroad couplers. Each car includes a pair of transverse stands for supporting the ribbon rail. The stands of each car are spaced 30 feet apart and 15 feet from the respective coupler such that the stands are spaced 30 feet apart along the length of the rail train. The stands each include multiple tiers (typically five or six tiers) which each support a plurality of rails, for example, eight to twelve rails per tier. The stands must each be strong enough both to support the weight of the rails and to resist side loads created by flexing of the ribbon rails as the rail train traverses curves in the track. Thirty-foot spacing for the stands is believed to be optimal for supporting the rails without excessive sagging.
The rails are loaded or threaded onto the rail train and across the shelves of the racks by a powered drive system. Considerable effort is required to carefully thread each rail into a desired pocket on each shelf. Loading the first rail on each shelf is the most difficult as it is difficult to thread the rail through the desired outer pocket of each rail support shelf, particularly when the rail train is setting on a curved section of track as the end of the rail wants to move in a straight line and the leading end tends to sag.
At least one car in each rail train is a tie-down car including a specialized stand that includes means for fixing the rails to the racks to prevent longitudinal movement of the rails relative to the tie-down car. The fixing means generally includes a plurality of clamping blocks that are bolted to the stand on opposite sides of each rail so as to bear against the foot or base flange of the rail and clamp it against the stand. Typically each clamping block is held down by three or four large bolts which must be installed or removed using an impact wrench or the like. All the other racks in the train allow for relative longitudinal movement of the rails and may include rollers that support the rails. This relative movement between the racks and the rails is required in order to allow the rails to flex without stretching or compressing as the train traverses curves in the track, as well as to allow for coupler slack that exists in each of the couplers between cars.
Each coupler has up to approximately six inches of slack. Coupler slack necessitates that the tie-down car be positioned near the center of the rail train so as to evenly divide the rails and to thereby insure that neither the forward end nor the rearward end of the rail can move a sufficient distance relative to the nearest adjacent rack that the end will fall off of the rack.
At the rearward end of the rail train is an end car from which the rails are unloaded. A rail-unloading machine is typically coupled to the end car and pulls the rails from the end car. The end car includes one or more stands and may include a barrier door rearward of the stand that swings inwardly across the car and acts as a stop to prevent the rails from sliding rearward off the rail train should one or more rails come loose from the tie-down car. The end car may also include a ramp which is pivotally mounted to the deck of the end car rearward of the swing door. The ramp includes a roller on its distal end. The distal end of the ramp can be raised or lowered relative to the deck of the end car and is used to guide the rails upwardly or downwardly as they are being unloaded.
Pickup of used rail follows a similar process. Typically a crane is provided to lift an end of a used ribbon rail and to aid in insertion of the end into a drive mechanism for pulling the rail off of the ground and driving it into a desired pocket in the stands on the a rail train. The used ribbon rails often must be cut to length to fit on the rail train or extended by coupling to a second piece of ribbon rail to fully fill the pocket of the rail train.
Cutting of the ribbon rail by known methods has several drawbacks. Cutting torches are often employed to cut the rail. This presents a potential for igniting fires in the surroundings from contact with the torch flame, dripping slag or molten metal, or with the very hot ends of the rail after cutting, as well as other dangers associated with operation of cutting torches.
Additionally, to cut the ribbon rail by known methods, workers are required to stand near the ribbon rail to operate the cutting torch, saw or other cutting apparatus. This places the worker in danger of being struck by loose ends of the ribbon rail upon completion of the cut because the rail may be under stress, e.g. bending stress that is released when the cut is completed. Further, current rail-pickup machines only provide a single drive apparatus for moving the ribbon rail. As such, after cutting, only one of the two pieces is moveable by the drive apparatus. To move the free piece of ribbon rail a crane is typically provided or the two ends can be rejoined by bolting together until the free piece is moved to a desired position and then the pieces are unbolted.
Extending of the sections of ribbon rail by known methods also has several drawbacks. As described above, current machines only provide a single drive apparatus. Thus, positioning the ends of two sections of ribbon rail together for joining can be difficult and may require workers to manually push or pull the rails by hand or with crowbars.
To join the two sections together a hole is drilled through the web of each of the sections near their abutting ends. A plate that includes similarly positioned holes therethrough is placed on one or both sides of the web and bolts are inserted therethrough. Workers thus must manually drill the holes in the sections of ribbon rail and install the coupling plate and bolts. Misalignment of the holes can result in play or slop in the joint or might require new holes to be drilled to achieve proper fit. And the worker is subject to the dangers of occupying the area near the ribbon rail, such as during movement of the rails to bring them into alignment for joining or resulting from abrupt movements that occur because of other movements of the rail train, workers, and equipment.
Improvements in the functionality and safety of rail loading and unloading machines are needed. It would be advantageous to provide a rail loading and unloading machine with dual drive apparatus positioned on opposite sides of a cutting station for moving opposite sections of a cut ribbon rail. It would also be advantageous to provide cutting and drilling stations that are operable by a worker from a safe vantage point. Additionally, it would be advantageous to provide a drilling station that prepares ribbon rail ends for coupling by simultaneously drilling at least a pair of holes through the web of the rail at designated locations. Further benefit would be realized in a rail loading and unloading machine configured to load or unload ribbon rails on either side of the machine and to simultaneously load, unload, or both load and unload ribbon rails on both sides of the machine.